| Author |
Message |
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Jay
#1 / 4
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 Unhandled Exception... Greetings! I have a runtime error that I'm hoping someone could help me with. The following is the error: Unhandled exception in Myprog.exe (NTDLL.DLL): 0xC0000005: Access Violation
Upon debugging, it is appartently related to the following assebly code in
NTDLL.DLL
77F51BAA inc dword ptr [eax+10h]
In my code the problem occurs once the following function is called:
png_read_info(png, info);
During debugging, both png and info seemed to be allocated fine.
The following is my fucntion:
void *png_read(unsigned *size_x, // image width
unsigned *size_y, // image height
unsigned *size_z, // number of channels
unsigned *depth, // datum depth in bytes
const char *filename, // path
bool byteize // convert to 8-bit depth when set
)
{
void *image;
FILE *fp;
png_bytep *row;
png_byte magic[8];
png_structp png;
png_infop info;
unsigned i;
//
// Wrapper for reading a PNG file.
//
ASSERT(!endian.is.little == !!endian.is.big, (""endian.is.little !=
!!endian.is.big));
if (!(fp = fopen(filename, "rb")))
{
fprintf(stderr, "can't open '%s': %s\n", filename, strerror(errno));
return NULL;
}
if (fread(magic, sizeof(magic), 1, fp) != 1) {
fprintf(stderr, "can't read '%s': %s\n", filename, strerror(errno));
fclose(fp);
return NULL;
}
if (!png_check_sig(magic, sizeof(magic)))
{
MessageBox(NULL,"This is not a PNG file" ,NULL, MB_OK);
fclose(fp);
return NULL;
}
if (!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
NULL)))
{
MessageBox(NULL,"PNG read struct allocation failed" ,NULL, MB_OK);
fclose(fp);
return NULL;
}
if (!(info = png_create_info_struct(png)))
{
fprintf(stderr, "PNG info struct allocation failed\n");
png_destroy_read_struct(&png, NULL, NULL);
fclose(fp);
return NULL;
}
if (setjmp(png_jmpbuf(png))) {
fprintf(stderr, "setjmp() failed\n");
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
return NULL;
}
png_init_io(png, fp);
png_set_sig_bytes(png, sizeof(magic));
png_read_info(png, info); // <----------------------- This point here
png_set_packing(png);
if (byteize)
{
png_set_strip_16(png);
}
else if (endian.is.little)
png_set_swap(png);
png_read_update_info(png, info);
ASSERT(info->bit_depth % CHAR_BIT == 0, ("info->bit_depth % CHAR_BIT !=
0"));
*size_x = (unsigned)info->width;
*size_y = (unsigned)info->height;
*size_z = (unsigned)info->channels;
if (depth)
*depth = (unsigned)info->bit_depth / CHAR_BIT;
if (!(row = (unsigned char **)malloc(*size_y * sizeof(png_bytep))) ||
!(image = row[*size_y - 1] = (unsigned char *)malloc(*size_y *
info->rowbytes))) {
fprintf(stderr, "malloc() for PNG data failed\n");
png_destroy_read_struct(&png, &info, NULL);
fclose(fp);
return NULL;
}
for (i = *size_y - 1; i; i--)
row[i - 1] = row[i] + info->rowbytes;
png_read_image(png, row);
png_read_end(png, NULL);
png_destroy_read_struct(&png, &info, NULL);
free(row);
fclose(fp);
return image;
Quote: }
Thanks, Jay
|
| Wed, 29 Jun 2005 11:16:02 GMT |
|
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Onkar Singh Parha
#2 / 4
|
Unhandled Exception... Where is png_read_info defined???? What does it do internally??? - Onkar
Quote: > Greetings! I have a runtime error that I'm hoping someone could help me > with. The following is the error: > Unhandled exception in Myprog.exe (NTDLL.DLL): 0xC0000005: Access
Violation
> Upon debugging, it is appartently related to the following assebly code in
> NTDLL.DLL
> 77F51BAA inc dword ptr [eax+10h]
> In my code the problem occurs once the following function is called:
> png_read_info(png, info);
> During debugging, both png and info seemed to be allocated fine.
> The following is my fucntion:
> void *png_read(unsigned *size_x, // image width
> unsigned *size_y, // image height
> unsigned *size_z, // number of channels
> unsigned *depth, // datum depth in bytes
> const char *filename, // path
> bool byteize // convert to 8-bit depth when set
> )
> {
> void *image;
> FILE *fp;
> png_bytep *row;
> png_byte magic[8];
> png_structp png;
> png_infop info;
> unsigned i;
> //
> // Wrapper for reading a PNG file.
> //
> ASSERT(!endian.is.little == !!endian.is.big, (""endian.is.little !=
> !!endian.is.big));
> if (!(fp = fopen(filename, "rb")))
> {
> fprintf(stderr, "can't open '%s': %s\n", filename, strerror(errno));
> return NULL;
> }
> if (fread(magic, sizeof(magic), 1, fp) != 1) {
> fprintf(stderr, "can't read '%s': %s\n", filename, strerror(errno));
> fclose(fp);
> return NULL;
> }
> if (!png_check_sig(magic, sizeof(magic)))
> {
> MessageBox(NULL,"This is not a PNG file" ,NULL, MB_OK);
> fclose(fp);
> return NULL;
> }
> if (!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
> NULL)))
> {
> MessageBox(NULL,"PNG read struct allocation failed" ,NULL, MB_OK);
> fclose(fp);
> return NULL;
> }
> if (!(info = png_create_info_struct(png)))
> {
> fprintf(stderr, "PNG info struct allocation failed\n");
> png_destroy_read_struct(&png, NULL, NULL);
> fclose(fp);
> return NULL;
> }
> if (setjmp(png_jmpbuf(png))) {
> fprintf(stderr, "setjmp() failed\n");
> png_destroy_read_struct(&png, &info, NULL);
> fclose(fp);
> return NULL;
> }
> png_init_io(png, fp);
> png_set_sig_bytes(png, sizeof(magic));
> png_read_info(png, info); // <----------------------- This point here
> png_set_packing(png);
> if (byteize)
> {
> png_set_strip_16(png);
> }
> else if (endian.is.little)
> png_set_swap(png);
> png_read_update_info(png, info);
> ASSERT(info->bit_depth % CHAR_BIT == 0, ("info->bit_depth % CHAR_BIT !=
> 0"));
> *size_x = (unsigned)info->width;
> *size_y = (unsigned)info->height;
> *size_z = (unsigned)info->channels;
> if (depth)
> *depth = (unsigned)info->bit_depth / CHAR_BIT;
> if (!(row = (unsigned char **)malloc(*size_y * sizeof(png_bytep))) ||
> !(image = row[*size_y - 1] = (unsigned char *)malloc(*size_y *
> info->rowbytes))) {
> fprintf(stderr, "malloc() for PNG data failed\n");
> png_destroy_read_struct(&png, &info, NULL);
> fclose(fp);
> return NULL;
> }
> for (i = *size_y - 1; i; i--)
> row[i - 1] = row[i] + info->rowbytes;
> png_read_image(png, row);
> png_read_end(png, NULL);
> png_destroy_read_struct(&png, &info, NULL);
> free(row);
> fclose(fp);
> return image;
> }
> Thanks, Jay
|
| Sat, 02 Jul 2005 02:54:30 GMT |
|
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Kobi Ben Tzv
#3 / 4
|
Unhandled Exception... Hi Jay,
You didn't provide code for the "png_read_info" function so its hard to say
where is the problem. Also I would suggest looking on call stack when the
exception occurs and this will help you to determine the problematic line
instead of problematic function.
Regards,
Kobi Ben Tzvi
Quote: > Greetings! I have a runtime error that I'm hoping someone could help me > with. The following is the error: > Unhandled exception in Myprog.exe (NTDLL.DLL): 0xC0000005: Access
Violation
> Upon debugging, it is appartently related to the following assebly code in
> NTDLL.DLL
> 77F51BAA inc dword ptr [eax+10h]
> In my code the problem occurs once the following function is called:
> png_read_info(png, info);
> During debugging, both png and info seemed to be allocated fine.
> The following is my fucntion:
> void *png_read(unsigned *size_x, // image width
> unsigned *size_y, // image height
> unsigned *size_z, // number of channels
> unsigned *depth, // datum depth in bytes
> const char *filename, // path
> bool byteize // convert to 8-bit depth when set
> )
> {
> void *image;
> FILE *fp;
> png_bytep *row;
> png_byte magic[8];
> png_structp png;
> png_infop info;
> unsigned i;
> //
> // Wrapper for reading a PNG file.
> //
> ASSERT(!endian.is.little == !!endian.is.big, (""endian.is.little !=
> !!endian.is.big));
> if (!(fp = fopen(filename, "rb")))
> {
> fprintf(stderr, "can't open '%s': %s\n", filename, strerror(errno));
> return NULL;
> }
> if (fread(magic, sizeof(magic), 1, fp) != 1) {
> fprintf(stderr, "can't read '%s': %s\n", filename, strerror(errno));
> fclose(fp);
> return NULL;
> }
> if (!png_check_sig(magic, sizeof(magic)))
> {
> MessageBox(NULL,"This is not a PNG file" ,NULL, MB_OK);
> fclose(fp);
> return NULL;
> }
> if (!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
> NULL)))
> {
> MessageBox(NULL,"PNG read struct allocation failed" ,NULL, MB_OK);
> fclose(fp);
> return NULL;
> }
> if (!(info = png_create_info_struct(png)))
> {
> fprintf(stderr, "PNG info struct allocation failed\n");
> png_destroy_read_struct(&png, NULL, NULL);
> fclose(fp);
> return NULL;
> }
> if (setjmp(png_jmpbuf(png))) {
> fprintf(stderr, "setjmp() failed\n");
> png_destroy_read_struct(&png, &info, NULL);
> fclose(fp);
> return NULL;
> }
> png_init_io(png, fp);
> png_set_sig_bytes(png, sizeof(magic));
> png_read_info(png, info); // <----------------------- This point here
> png_set_packing(png);
> if (byteize)
> {
> png_set_strip_16(png);
> }
> else if (endian.is.little)
> png_set_swap(png);
> png_read_update_info(png, info);
> ASSERT(info->bit_depth % CHAR_BIT == 0, ("info->bit_depth % CHAR_BIT !=
> 0"));
> *size_x = (unsigned)info->width;
> *size_y = (unsigned)info->height;
> *size_z = (unsigned)info->channels;
> if (depth)
> *depth = (unsigned)info->bit_depth / CHAR_BIT;
> if (!(row = (unsigned char **)malloc(*size_y * sizeof(png_bytep))) ||
> !(image = row[*size_y - 1] = (unsigned char *)malloc(*size_y *
> info->rowbytes))) {
> fprintf(stderr, "malloc() for PNG data failed\n");
> png_destroy_read_struct(&png, &info, NULL);
> fclose(fp);
> return NULL;
> }
> for (i = *size_y - 1; i; i--)
> row[i - 1] = row[i] + info->rowbytes;
> png_read_image(png, row);
> png_read_end(png, NULL);
> png_destroy_read_struct(&png, &info, NULL);
> free(row);
> fclose(fp);
> return image;
> }
> Thanks, Jay
|
| Thu, 30 Jun 2005 22:03:06 GMT |
|
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George Zheng [M
#4 / 4
|
Unhandled Exception... Hi,
Try to debug your application in VC. When this exception occurs, check the
source stack. It can help you position the exact code position instead of
the function.
This posting is provided "AS IS" with no warranties, and confers no rights.
George Zheng [MSFT]
|
| Sat, 02 Jul 2005 17:02:47 GMT |
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